function::operator=

取代儲存可呼叫的物件。

function& operator=(null_ptr_type npc);
function& operator=(const function& right);
template<class Fty>
    function& operator=(Fty fn);
template<class Fty>
    function& operator=(reference_wrapper<Fty> fnref);

參數

• npc
  null 指標常數。

• right
  要複製的函式物件。

• fn
  要包裝的可呼叫的物件。

• fnref
  在一組可呼叫的物件參考。

備註

運算子不同的名稱為傳遞至的運算元的可呼叫的物件取代 *this 持有的可呼叫的物件。

範例

// std_tr1__functional__function_operator_as.cpp 
// compile with: /EHsc 
#include <functional> 
#include <iostream> 
 
int neg(int val) 
    { 
    return (-val); 
    } 
 
int main() 
    { 
    std::function<int (int)> fn0(neg); 
    std::cout << std::boolalpha << "empty == " << !fn0 << std::endl; 
    std::cout << "val == " << fn0(3) << std::endl; 
 
    std::function<int (int)> fn1; 
    fn1 = 0; 
    std::cout << std::boolalpha << "empty == " << !fn1 << std::endl; 
 
    fn1 = neg; 
    std::cout << std::boolalpha << "empty == " << !fn1 << std::endl; 
    std::cout << "val == " << fn1(3) << std::endl; 
 
    fn1 = fn0; 
    std::cout << std::boolalpha << "empty == " << !fn1 << std::endl; 
    std::cout << "val == " << fn1(3) << std::endl; 
 
    fn1 = std::cref(fn1); 
    std::cout << std::boolalpha << "empty == " << !fn1 << std::endl; 
    std::cout << "val == " << fn1(3) << std::endl; 
 
    return (0); 
    } 
 

需求

標題: <functional>

命名空間: std

請參閱

參考

function Class

function::function

function::swap